The white-throated sparrow is a passerinebird of the American sparrow family Passerellidae. It measures 15 to 19 cm (5.9 to 7.5 in) in length with a wingspan of 23 cm (9.1 in). Typical weight is 22 to 32 g (0.78 to 1.13 oz), with an average of 26 g (0.92 oz).[3][4] Among standard measurements, the wing chord is 6.3 to 7.9 cm (2.5 to 3.1 in), the tail is 6.8 to 7.7 cm (2.7 to 3.0 in), the bill is 1 to 1.2 cm (0.39 to 0.47 in) and the tarsus is 2.2 to 2.4 cm (0.87 to 0.94 in).[5] They are similar in appearance to the white-crowned sparrow, but with white throat markings and yellow lores.

There are two adult plumage variations known as the tan-striped and white-striped forms. On the white-striped form the crown is black with a white central stripe. The supercilium is white as well. The auriculars are gray with the upper edge forming a black eye line.[3]

On the tan form, the crown is dark brown with a tan central stripe. The supercilium is tan as well. The auriculars are gray/light brown with the upper edge forming a brown eye line. Both variations feature dark eyes, a white throat, yellow lores and gray bill.[3] There is variation and some individuals may show dark lateral stripes of each side of the throat.

They almost always pair with the opposite color morph for breeding. The two color morphs occur in approximately equal numbers. Both male and female white-striped birds are more aggressive than tan-striped birds during the breeding season.[6][7]

The breast has gray/tan streaks and the streaks continue down the flanks but the belly is generally light gray. The wings are rufous with two distinct white wing bars. Sexes are morphologically similar.[3]

White-throated sparrows breed in central Canada and New England. They nest either on the ground under shrubs or low in trees in deciduous or mixed forest areas and lay three to five brown-marked blue or green-white eggs.

Despite a high level of con-specific rivalry within white-throated sparrows, this species is often dominated by other seed-eating winter residents, even those that are no larger than itself like the song sparrow, and thus may endure high levels of predation while foraging since restricted to sub-optimal sites at times by competition.[9] Not to mention numerous mammalian carnivores, at least ten avian predators often hunt them and they are among the most regular prey species for some smaller raptors, i.e. the sharp-shinned hawk and eastern screech-owl.[10][11]

There are at least two distinct songs sung by this species. One consists of an initial note, followed by three or so repeated notes at an interval of about a major third above. The second song consists of an initial note, a second a whole step lower, and a third note, repeated two or three times, about a minor third below that. This second song is commonly described by use of mnemonics with the cadence of "Po-or Sam Peabody, Peabody, Peabody" (or "O-oh sweet Canada, Canada, Canada") The rhythm is very regular, and the timbre could be described as pinched. These musical intervals are only approximate; to a human ear the song often sounds out of tune. The repeated note will often change in pitch very slightly, contributing to this effect.

The white-throated sparrow also has at least two calls, in addition to its song.

^Bock, C. E.; Prickles, R. E. (1983). "Range size and local abundance of some North American songbirds: a positive correlation". The American Naturalist. 122 (2): 295–299. doi:10.1086/284136. JSTOR2461236.